Alkylene oxide polymers are products of polymerization of alkylene oxide. In general, they are water soluble polymers superb in promoting coagulation, dispersion, increased viscosity and so on. Because of these functions, the alkylene oxide polymers are utilized widely in such applications as pulp dispersion agents, resin modifiers, binders, coagulants, detergents, foods, personal care products, hygiene materials, cosmetics, medicines and quasi-medicines.
Alkylene oxide is a chemical compound having an ether ring structure shown in the following structural formula I: 
Typical alkylene oxides include ethylene oxide shown in the structural formula II and propylene oxide shown in the structural formula III: 
Polymerization of alkylene oxide is promoted by a variety of polymerization initiators or catalysts such as alkalis, boron trifluoride, oxides of alkaline earth metals, and organic metal compounds. When ethylene oxide for example is polymerized, polymers having a structure shown in the following formula IV are produced: 
It is known that polymerization reaction of the alkylene oxide differs in terms of degree of polymerization and/or rate of polymerization depending on the kind of catalyst utilized. For example, when the catalyst is a product obtained by reaction of an organic compound of Zn or Al with alcohol, the resulting polymerization reaction is a coordination polymerization and resulting alkylene oxide polymers have a relatively high degree of polymerization. Backed by such knowledge, research and development efforts have been concentrated so far on improvement of catalysts in view of increased rate of reaction and yield.
For example, the Japanese Patents Nos. 45-7751 and 53-27319 disclose that when an organic zinc compound is reacted with multifunctional compounds (such as polyhydric alcohols, polyhydric thiols, polyhydric phenols and polyhydric thiophenols) and then with a monohydric alcohol, the obtained product acts as a superb catalyst in the alkylene oxide polymerization reaction. Also, the Japanese Patent Laid-open No. 62-232433 discloses that when an organic zinc compound and a polyhydric alcohol are reacted with each other under contact with fine particles of metal oxides and a nonionic surfactant, the obtained product acts as a superb catalyst in the alkylene oxide polymerization reaction. Whichever catalyst is utilized, the alkylene oxide polymerization reaction is made in an n-hexane solvent.
The above Japanese Patents Nos. 45-7751 and 53-27319 disclose processes for production capable of obtaining alkylene oxide polymers having a relatively high degree of polymerization, since the catalysts prepared as described above serves-in homopolymerization of an alkylene oxide or copolymerization of two or more kinds of alkylene oxides. However, there are problems with the processes disclosed by these documents. Specifically, the rate of polymerization is low, and the yield is insufficient. Further, reproducibility of the degree of polymerization in the obtained polymers is relatively low. In addition, the product of polymerization sometimes becomes massive, which makes stable industrial production difficult.
On the other hand, according to a process for production disclosed in the Japanese Patent Laid-open No. 62-232433, reproducibility of the degree of polymerization in the obtained polymers is relatively good, but catalyst preparation requires a very complex operation, and rate of polymerization is relatively low.